Correlation between Surface Morphology and Corrosion Behaviour of Ni-P-Graphene and Ni-P-Carbon Nanotube Composite Coatings

Atul Meshram, M. K. Punith Kumar, Chandan Srivastava
2021 Microscopy and Microanalysis  
It has been shown recently that incorporation of graphene and carbon nanotubes (CNTs) into conventional metallic coatings leads to significant enhancement in the corrosion resistance behaviour of the coatings [1]. This enhancement is primarily due to the inert and impermeable nature of graphene and hydrophobicity of the carbon nanotubes. The optimum volume fraction of these carbonaceous additives (in the coating matrix) which can yield the lowest corrosion rate however need to be determined for
more » ... every composite coating system as a lower additive amount can lead to inhomogeneous microstructure which is detrimental for corrosion resistance and a larger additive amount can lead to detrimental galvanic coupling where the carbonaceous additive (present as major phase) acts as cathode and the metallic matrix (present as minor phase) acts as anode. On more important aspect that is the effect of incorporation of carbonaceous additives on the morphological evolution and corrosion behaviour is illustrated here. Amorphous Ni-P coatings exhibit properties such as excellent corrosion and wear resistance. In this work the effect of incorporation of graphene and CNT on the morphology and electrochemical behaviour of Ni-Pgraphene and Ni-P-CNT composite coating was investigated. Ni-P-graphene and Ni-P-CNT composite coatings were electrodeposited over mild steel substrate using the watts bath. Graphene synthesis was done by the electrochemical exfoliation of graphite [2] and CNTs were synthesised using the chemical vapour deposition technique [3] . Different amounts of the functionalized graphene and CNTs were dispersed in the aqueous electrolyte bath to produce Ni-P-graphene and Ni-P-CNT composite coatings with different volume fractions of the additives.
doi:10.1017/s1431927621001847 fatcat:a2itrxcsqngxlnfq7c2a43hrxe